| 124. Binary Tree Maximum Path Sum | | | Solve | Hard | | |
| 272. Closest Binary Search Tree Value II | | | Solve | Hard | | |
| 297. Serialize and Deserialize Binary Tree | | | Solve | Hard | | |
| 428. Serialize and Deserialize N-ary Tree | | | Solve | Hard | | |
| 431. Encode N-ary Tree to Binary Tree | | | Solve | Hard | - | |
| 834. Sum of Distances in Tree | | | Solve | Hard | | |
| 968. Binary Tree Cameras | | | Solve | Hard | | |
| 987. Vertical Order Traversal of a Binary Tree | | | Solve | Hard | | |
| 1028. Recover a Tree From Preorder Traversal | | | Solve | Hard | | |
| 1373. Maximum Sum BST in Binary Tree | | | Solve | Hard | | |
| 1377. Frog Position After T Seconds | | | Solve | Hard | | |
| 1483. Kth Ancestor of a Tree Node | | | Solve | Hard | | |
| 1516. Move Sub-Tree of N-Ary Tree | | | Solve | Hard | | |
| 1569. Number of Ways to Reorder Array to Get Same BST | | | Solve | Hard | | |
| 1597. Build Binary Expression Tree From Infix Expression | | | Solve | Hard | | |
| 1617. Count Subtrees With Max Distance Between Cities | | | Solve | Hard | | |
| 1719. Number Of Ways To Reconstruct A Tree | | | Solve | Hard | | |
| 1766. Tree of Coprimes | | | Solve | Hard | | |
| 1916. Count Ways to Build Rooms in an Ant Colony | | | Solve | Hard | | |
| 1932. Merge BSTs to Create Single BST | | | Solve | Hard | - | |
| 2003. Smallest Missing Genetic Value in Each Subtree | | | Solve | Hard | | |
| 2005. Subtree Removal Game with Fibonacci Tree | | | Solve | Hard | | |
| 2246. Longest Path With Different Adjacent Characters | | | Solve | Hard | | |
| 2277. Closest Node to Path in Tree | | | Solve | Hard | | |
| 2313. Minimum Flips in Binary Tree to Get Result | | | Solve | Hard | | |
| 2322. Minimum Score After Removals on a Tree | | | Solve | Hard | | |
| 2421. Number of Good Paths | | | Solve | Hard | | |
| 2440. Create Components With Same Value | | | Solve | Hard | | |
| 2458. Height of Binary Tree After Subtree Removal Queries | | | Solve | Hard | | |
| 2479. Maximum XOR of Two Non-Overlapping Subtrees | | | Solve | Hard | | |
| 2509. Cycle Length Queries in a Tree | | | Solve | Hard | | |
| 2538. Difference Between Maximum and Minimum Price Sum | | | Solve | Hard | | |
| 2581. Count Number of Possible Root Nodes | | | Solve | Hard | - | |
| 2603. Collect Coins in a Tree | | | Solve | Hard | | |
| 2646. Minimize the Total Price of the Trips | | | Solve | Hard | | |
| 2791. Count Paths That Can Form a Palindrome in a Tree | | | Solve | Hard | - | |
| 2792. Count Nodes That Are Great Enough | | | Solve | Hard | - | |
| 2846. Minimum Edge Weight Equilibrium Queries in a Tree | | | Solve | Hard | | |
| 2867. Count Valid Paths in a Tree | | | Solve | Hard | | |
| 2872. Maximum Number of K-Divisible Components | | | Solve | Hard | | |
| 2920. Maximum Points After Collecting Coins From All Nodes | | | Solve | Hard | | |
| 2973. Find Number of Coins to Place in Tree Nodes | | | Solve | Hard | | |
| 3068. Find the Maximum Sum of Node Values | | | Solve | Hard | - | |
| 3203. Find Minimum Diameter After Merging Two Trees | | | Solve | Hard | - | |
| 3241. Time Taken to Mark All Nodes | | | Solve | Hard | - | |
| 3313. Find the Last Marked Nodes in Tree | | | Solve | Hard | - | |
| 3327. Check if DFS Strings Are Palindromes | | | Solve | Hard | - | |
